Sóng cơ và Sóng âm Practice Questions
THPT (Vietnam) · THPT Vật lý · 146 free MCQs with instant results and detailed explanations.
146
Total
45
Easy
77
Medium
24
Hard
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Sample Questions from Sóng cơ và Sóng âm
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Q1
Easy
What is the speed of sound in air at room temperature (20°C)?
A.
343 m/s
B.
300 m/s
C.
1500 m/s
D.
1000 m/s
Show Answer & Explanation
Correct Answer: A
The speed of sound in air at 20°C is approximately 343 meters per second. This value is widely accepted in physics and is based on the temperature and density of air.
Q2
Easy
Which of the following describes a longitudinal wave?
A.
Particles move perpendicular to wave direction
B.
Particles move parallel to wave direction
C.
Particles are at rest
D.
Particles move in circular motion
Show Answer & Explanation
Correct Answer: B
In a longitudinal wave, the particles of the medium move parallel to the direction of the wave propagation. This is characteristic of sound waves, where compressions and rarefactions occur.
Q3
Easy
What happens to the pitch of a sound when the frequency increases?
A.
The pitch decreases
B.
The pitch remains the same
C.
The pitch increases
D.
The pitch becomes inaudible
Show Answer & Explanation
Correct Answer: C
As the frequency of a sound wave increases, the pitch of the sound also increases. Higher frequency corresponds to a higher pitch, which is perceived by the human ear.
Q4
Medium
What is the primary factor that determines the speed of a sound wave in a medium?
A.
Density of the medium
B.
Temperature of the medium
C.
Humidity of the medium
D.
Frequency of the wave
Show Answer & Explanation
Correct Answer: B
The speed of sound in a medium is primarily affected by the temperature; as temperature increases, the speed of sound also increases due to the increased kinetic energy of the molecules in the medium.
Q5
Medium
A tuning fork produces a sound wave with a frequency of 440 Hz. If the speed of sound in air is 344 m/s, what is the wavelength of the sound wave?
A.
0.78 m
B.
1.0 m
C.
0.56 m
D.
1.25 m
Show Answer & Explanation
Correct Answer: A
Wavelength can be calculated using the formula: wavelength = speed of sound / frequency. Thus, wavelength = 344 m/s / 440 Hz = 0.78 m.
Q6
Medium
When a sound wave enters a denser medium, how does its speed change?
A.
Speed increases
B.
Speed decreases
C.
Speed remains constant
D.
Speed doubles
Show Answer & Explanation
Correct Answer: B
When a sound wave moves from a less dense medium to a denser medium, its speed decreases due to the increased inertia of the denser particles which resist the wave's movement.
Q7
Medium
Which of the following best describes the phenomenon of resonance in sound waves?
A.
Sound waves reflect off surfaces
B.
Sound waves combine to form a single wave
C.
An object vibrates at its natural frequency due to external vibrations
D.
Sound waves are absorbed by a medium
Show Answer & Explanation
Correct Answer: C
Resonance occurs when an object is forced to vibrate at its natural frequency by an external sound wave, leading to an increase in amplitude of the vibrations.
Q8
Hard
A tuning fork produces a sound wave of frequency 440 Hz. If the speed of sound in air is approximately 343 m/s, what is the wavelength of the sound wave produced by the tuning fork?
A.
0.78 m
B.
1.00 m
C.
0.50 m
D.
0.60 m
Show Answer & Explanation
Correct Answer: A
The wavelength can be found using the formula: wavelength = speed of sound / frequency. Here, that is 343 m/s ÷ 440 Hz ≈ 0.78 m, making option A the correct answer.
Q9
Hard
A wave traveling in a string is described by the equation y(x, t) = A sin(kx - ωt). If the amplitude A is 0.02 m, the wave number k is 4 rad/m, and the angular frequency ω is 50 rad/s, what is the maximum speed of a point on the string?
A.
1.00 m/s
B.
0.40 m/s
C.
0.10 m/s
D.
0.80 m/s
Show Answer & Explanation
Correct Answer: A
The maximum speed of a point on the string is given by the formula: v_max = Aω. Substituting the values: 0.02 m * 50 rad/s = 1.00 m/s, confirming option A is correct.
Q10
Hard
A tuning fork vibrates at a frequency of 440 Hz. If the speed of sound in air is 340 m/s, what is the wavelength of the sound produced by the tuning fork?
A.
0.77 m
B.
0.68 m
C.
0.85 m
D.
0.90 m
Show Answer & Explanation
Correct Answer: A
The wavelength can be calculated using the formula λ = v/f, where v is the speed of sound and f is the frequency. Here, λ = 340 m/s / 440 Hz = 0.7727 m, which rounds to 0.77 m.
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Sóng cơ và Sóng âm — THPT (Vietnam) THPT Vật lý Practice Questions Online
This page contains 146 practice MCQs for the chapter Sóng cơ và Sóng âm in THPT (Vietnam) THPT Vật lý. The questions are organized by difficulty — 45 easy, 77 medium, 24 hard — so you can choose the right level for your preparation.
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